The present invention is directed to a device for releasably connecting two parts of a dental handpiece together which device enables a quick connection and disconnection of the parts without the assistance of tools and can be used for connecting a head piece to the grip section or for connecting a dental handpiece part to a hose mount or other parts.
In the dental handpiece disclosed in German A.S. 17 66 598, a connecting device includes an annular groove arranged in one of the handpiece parts which receives a radially removable spring loaded pin provided on the other part. In this manner, one of the handpiece parts is protected against inadvertent axial slippage but can be turned around the longitudinal axis. Since a certain axial travel must be had for the engagement of the pin into the annular groove, the device does not provide a friction-type locking together of the two parts. Moreover, the actuation button or handle for unlocking the pin projects radially from the handpiece and can be disruptive.
An axial friction-type locking of the handpiece parts is known and is provided in the form of bayonet catches or joints as disclosed in German A.S. 12 19 170. However, in this type of connection, a twisting of the two handpiece parts with respect to one another is necessary. However, a twisting of the handpiece parts is not always desireable particularly in dental handpiece and angled handpieces which have cooling agent lines incorporated therein. Since one would need to provide flat casket rings at the connecting ends for the cooling lines and a relatively high compression force is required on these casket rings in order to seal the cooling line connections, a bayonet type friction locking device is not desireable in a dental handpiece having cooling lines.